ESTIMATE OF METHANE GENERATION IN EXPERIMENTAL LANDFILL LOCATED AT MURIBECA LANDFILL-BRAZIL USING SIMPLIFIED METHODS

SUMMARY: There are several mathematical models that can be used to estimate the generation of gas in landfill waste. These models can be classified as biocinetics and global. The mathematical equations that represent the biocinetics model is more complex because require the coupling of general and constitutive equations of the model involving other factors in the generation of gas like gas and liquid flow, heterogeneity of the material, mechanical behavior, microbial decomposition, pH, temperature and the influence of other external factors such as atmospheric pressure and other climate conditions. Global models consist of equations more simplified that grouping the phenomena of degradation in exponential equations, providing gas generation versus time and some experimental calibration parameter, usually the gas generation potential and decay rate constant. Within these models are included models obtained by Biochemical Methane Potencial (BMP) testing and the model of School Canyon (adopted by EPA, World Bank, IPCC). These models are considered simplified and are widely used to estimate the approximate gas generation in MSW landfills in Brazil. In this context, this work has two global models more used in Brazil (US-EPA 2005, IPCC 2006) for estimating methane generation in an experimental landfill, located in Muribeca landfill – Brazil, comparing the results generated by models with those obtained experimentally by monitoring of the gas generation. With this work was possible to observe that IPCC's model (2006) has represent better the behavior of the methane generation in the experimental landfill, which considers certain waste characteristics, as specific heterogeneity and kinetics of degradation. This work has early studies for the development of a mathematical model in house, which solves coupled fluid, gas, thermal flow and mechanical problems in landfills at the Federal University of Pernambuco.